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Calculating your country’s odds in the qualifying rounds for the 2018 FIFA World Cup

March 22, 2016

Brazil and Uruguay are the top favorites. Ecuador has been the most positive surprise.

We have used econometric techniques to calculate the odds of the different national teams reaching the 2018 World Cup finals in Russia. In order to calculate each team’s probability of success, we initially estimated an initial probability based on the characteristics of the national teams. We have now adjusted these initial figures based on results seen on the football pitch.

During the South American qualifying rounds for the 2014 World Cup, we wrote a series of articles estimating the probability of each South American national team’s succeeding in the qualifying rounds.

Our predictions proved to be solid! We concluded that Argentina, Uruguay and Chile would make it to the World Cup. To Colombia, which also qualified, we had given good initial odds, although it was not among our early favorites. But upsets have always been a part of football. We also did not believe that Ecuador would qualify. Not only did they qualify, but they also had a good performance in the World Cup in Brazil.

The qualifying rounds for the World Cup in Russia are already underway. On the eve of another round of qualifiers, we have decided to return to our model for South America.

In the South American qualifiers all nations play each other, in a double round-robin (home and away). Therefore, each of the ten teams will face every other team twice. After these eighteen games, the top four teams will qualify directly for the 2018 FIFA World Cup. The fifth-place team will advance to a playoff against an team from Oceania.

Initial probabilities

We have used an econometric model (Probit) to estimate the initial probability of qualifying. We have noticed that, historically, a team’s probability of qualifying correlates to: i) the recent performance of the national team, as measured by its FIFA ranking; and ii) the number of times that country’s team has participated in previous World Cups. The results of this model for the current World Cup qualifying rounds are shown in Table 1. Based on initial probabilities, the top favorites are Brazil, Argentina and Uruguay. Chile, the current Copa America holder, also starts off with a high probability of qualifying. Colombia and Ecuador are close behind. At the bottom is Venezuela, with an initial probability below 5%.

First rounds

The first qualifying rounds took place at the end of last year. With these results in hand (Table 2), we can update the initial probabilities discussed above. To do so, we will calculate a second probability that takes into account the results of the games only. The final probability will be the weighted average of the initial probability and the performance-based probability. The weightings will be proportional to the number of matches that have already been played. (So far, four matches have been played – 22% of the total. Therefore, the initial probability will have a weighting of 78%, while the probability drawn from the performances will have a weighting of 22%.)

To calculate the probability drawn from the results, we could just extrapolate the performance in the first matches to the rest of the competition in a linear way. However, an analysis of previous qualifiers shows that the teams that perform the best at the beginning tend to lose momentum in later rounds, opening room for other teams to start to bounce back (Chart 1). We have adjusted the forecast to take account of this pattern.

Final probability

Each team’s final probability of qualifying – the weighted average of its initial probability and its performance probability – is shown in Table 3. Brazil and Uruguay remain at the top of the table, as the results on the field have so far confirmed their initial advantages. Argentina trails closely behind, with a final probability above 80%. But the Argentinians have to pick up their game and improve their performance if they want to maintain their favorable odds of qualifying. Chile, which started off with a good initial probability and has performed well since, rounds out the top four.

But was Ecuador the real standout of the first rounds, with four wins out of four. Due to its infrequent participation in previous World Cups, Ecuador’s national team did not begin with a high probability. But a high FIFA ranking (13th) already hinted that the team could be a dark horse. Ecuador’s probability now ranks higher than that of Colombia’s team, one of the sensations of the 2014 World Cup, which has James Rodrigues and Juan Cuadrado among its starters. The dispute for the fifth-place, that also includes Paraguay, will be intense!

At the bottom of the table, there were no surprises. Venezuela has never qualified for the World Cup and holds (by far) the lowest position in the FIFA ranking among all the participants. They have lost all their matches so far, and it is highly unlikely that they will be playing in Russia in 2018.